1. Field of the Invention
The present invention relates to a recording apparatus comprising a copying system for copying an original document on a document table onto recording paper, and a printing system for printing information received from outside, whereby the recording apparatus not only has a document copying function but also acts as a hard copy output terminal of a computer and the like.
2. Description of the Prior Art
Known optical printers include a laser beam printer and an LED printer which employ an electrophotographic process. Considering such an optical printer and an electrostatic, indirect type copying machine employing the electrophotographic process, one will realize that these printer and copying machine have in common the various devices that take part in the processes subsequent to electrostatic image formation on a photosensitive member. It will become possible to achieve a recording apparatus having the above-mentioned two functions at low cost if such common devices are effectively used, e.g. by incorporating an optical printing head into the electrostatic, indirect type copying machine for converting printing information received from outside into optical information and selectively exposing surfaces of the photosensitive member.
Such an optical printing head forming part of the printing system may be disposed adjacent the photosensitive member of the copying machine in order to promote effective use of the two functions for improved operating efficiency. Where the printing system is connected to a forwarding device for supplying printed recording paper to the document table, the recording paper itself, on which image information output from a computer or the like to the printing system is printed, namely a hard copy, may be used as an original document to be copied by the copying system. It is thus sufficient to obtain the image information from the computer or the like only once even where a plurality of hard copies are required. Consequently, the computer or the like is promptly made available for other uses. Such a proposal is disclosed in Japanese Patent Publication No. 61-19033, for example.
However, the known recording apparatus noted above has the following disadvantage since printed recording paper is fed directly to the document table. No problem arises where a plurality of hard copies of a single page are produced from the image information provided by the computer or the like. An inconvenience does occur, however, where hard copies of plural pages are produced to act as original documents. That is, because the copying and printing systems share one photosensitive member, the printing system must wait to carry out a printing operation before one sheet of copying paper printed in the previous printing operation, namely a hard copy of a preceding page, and placed on the document table as an original document is copied by the copying system to produce a plurality of duplicates. Consequently, a hard copy of each page is printed in response to the image information from the computer or the like only after copying of the previous printout is completed. This requires the computer or the like acting as the image information source to output the image information intermittently to the printing system. Although the computer or the like may be used for other purposes during the standby period from one hard copy output to another, the hard copy output operation cannot be carried out continuously.